import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TcpEchoServer {
    private ServerSocket serverSocket = null;
    public TcpEchoServer(int port) throws IOException {
        serverSocket = new ServerSocket(port);
    }
    public void start() throws IOException {
        System.out.println("启动服务器");
        ExecutorService executorService = Executors.newCachedThreadPool();
        while(true){
            Socket clientSocket = serverSocket.accept();
            executorService.submit(()->{
                processConnection(clientSocket);
            });
        }

    }

    private void processConnection(Socket clientSocket) {
        System.out.printf("[%s:%d]客户端上线\n",clientSocket.getInetAddress(),clientSocket.getPort());
        try(InputStream inputStream = clientSocket.getInputStream();
            OutputStream outputStream = clientSocket.getOutputStream()) {
            Scanner scanner = new Scanner(inputStream);
            PrintWriter writer = new PrintWriter(outputStream);
            while (true){
                if(!scanner.hasNext()){
                    System.out.printf("[%s:%d]客户端下线\n",clientSocket.getInetAddress(),clientSocket.getPort());
                    break;
                }
                String request = scanner.next();
                String response = process(request);
                writer.println(response);
                writer.flush();
                System.out.printf("[%s:%d]req:%s,resp:%s\n",clientSocket.getInetAddress(),clientSocket.getPort(),request,response);
            }

        } catch (IOException e) {
            throw new RuntimeException(e);
        }finally {
            try {
                clientSocket.close();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
    }

    private String process(String request) {
        return request;
    }

    public static void main(String[] args) throws IOException {
        TcpEchoServer server = new TcpEchoServer(9090);
        server.start();
    }
}
